1. Field of the Invention
The present invention relates automation of the manufacture of trouser closures for fly openings, and more particularly to a method of and apparatus for detecting ends of a succession of fly strips connected end to end by a slide fastener chain.
2. Prior Art
In the manufacture of trouser closures for fly openings, a slide fastener chain, to which a succession of fly strips is attached, is fed to an intermittently operating apparatus for forming element-free gaps in the fastener chain. To this end, it has been the common practice to detect ends of the successive fly strips in order to automatically control the intermittent operation of the element-free gap forming apparatus; confronting ends of an adjacent pair of the fly strips are sensed by a feeler or other mechanical means. However, the successive fly strips are connected end to end in substantially abutting relation with only a very small space between an adjacent pair of the fly strips. With this smallness of the inter-fly spaces, accurate detection of the fly ends is difficult to achieve. U.S. Pat. No. 3,570,104, issued Mar. 16, 1971 to P. B. Jensen, is believed to exemplify the prior art.